import java.util.Scanner;

public class J2411082 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        String rec = func(str);
        System.out.println(rec);
    }
    public static String func(String str){
//        StringBuffer stringBuffer = new StringBuffer();
        String str1 = "";
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if(!str.contains(ch+"")){
                str1 += ch;
            }
        }return str1;
    }
}
